For years, information technology (IT) organizations (the “providers”) have offered IT management services and computing resources to other businesses (the “customers”) within a utility computing environment. While a customer may purchase or lease IT resources directly from a provider for that customer's exclusive benefit, a customer also may share a provider's computing resources and management services with other customers. In a typical utility computing environment, the customer does not purchase or lease the physical resources; instead, the provider retains the discretion to allocate the resources as needed to meet its service obligations. Nonetheless, the provider must meet the requirements of each customer sharing the IT resources as specified in a contract or an agreement. If these service requirements are not met, the provider has breached its service obligation to the customer and the provider must compensate the customer for the breach.
As illustrated in FIG. 1, customers of on-demand services share management and computing resources (to the system and subsystem level), including persistent memory (“storage”), volatile memory (“memory”), and processors. FIG. 1 portrays another characteristic of the on-demand model—multiple customers sharing the same subsystem within the same computing resource, such as a logical partition (LPAR). In FIG. 1, for example, customer 3 and customer 4 each could run separate instances of operating system 3, such as International Business Machines, Inc.'s (IBM) Z/LINUX, on a single Z/VM (also by IBM) LPAR. When multiple external customers share the same hardware, as described here, performance tuning of the system must be applicable to both the workload and to all customers sharing the hardware.
A Service Level Agreement (SLA) typically is used in an on-demand shared environment to establish to threshold levels of service and guide the dynamic allocation of IT resources. The SLA is a contract, or series of contracts, that embodies the mutual understandings between the provider and the customer. Thus, any failure to provide the agreed level of service to a customer is referred to herein as an “SLA breach” or “breach.” The SLA also sets system (and subsystem) performance expectations and defines the procedures and reports needed to track compliance to the agreement. The SLA may contain the process for reporting service problems, the time frame for problem resolution, the process for monitoring service levels, and the penalties associated with any given SLA breach.
A performance monitoring tool, commonly referred to as a profiling tool, collects performance data to determine compliance with the SLA. The profiling tool tracks and measures performance characteristics of the system including CPU utilization, processing time, and the memory or storage available to a customer. Often, these tools axe designed to operate in a particular environment. Performance Monitoring Infrastructure Request Metrics is an example of a profiling tool designed to operate after deployment in a web-based environment. Additionally, system administrators use the information obtained from these performance measurements (“metrics”) to tune the performance of the system and take corrective action if needed. When the profiling tool indicates that system resources are not available, or arc not performing according to the SLA, the SLA is breached. The provider pays a penalty to compensate the customer for the SLA breach according to the terms of the SLA.
One of the fundamental tenets of a utility computing environment is the concept of proactively rebating, i.e., compensating, a customer when an SLA is breached. In a typical on-demand scenario, the various customers hosted by a single provider agree to different levels of service and compensation or “rebate” for an associated breach. For example, some of these customers may be “premium” customers, who pay more for higher service levels and are entitled to greater compensation when there is an SLA breach. These premium customers consequently represent a greater penalty to the provider in the event of an SLA breach. Other customers may subscribe as “standard” customers, who pay relatively less for the services, receive less compensation when there is a breach, and thus, represent a lesser degree of penalty in the event of an SLA breach. A sample scenario is provided in FIG. 2.
In addition to using profiling tools, there are several methods available to IT service providers in the utility computing environment to measure compliance with an SLA. Some of these methods also calculate appropriate rebates to customers in the event of an SLA breach, and proactively disburse a rebate to a customer. These processes are disclosed in U.S. Pat. No. 6,195,697 (issued Feb. 27, 2001), U.S. Pat. No. 6,556,659 (issued Apr. 29, 2003), and U.S. patent application No. 10/166,796. These processes do not address optimizing network resources and managing conflicting needs among the customers of the shared network collectively, nor do these processes address reallocating resources among the customers to minimize the total rebate awarded in the event of an SLA breach.
Patent application Ser. No. 0062205 (published Apr. 1, 2004) assigns a financial value to identified performance flows based on SLA requirements and penalties for breach of the requirements. This financial value alerts operators of the possible financial impacts of reconfiguring hardware or software associated with those identified flows. This process, however, merely calculates and displays the financial loss associated with a breach or potential breach of one individual customer's SLA. U.S. patent application No. 10/675,726 does provide a method for estimating an SLA breach value, based on data acquired from an individual customer and on data acquired from an aggregated group of customers. But again, this method does not disclose a means for minimizing the total rebate a service provider must offer when an SLA is breached.
Thus, the tools used to track and measure the performance characteristics of transactions throughout a system to determine compliance to an SLA are common. Similarly, processes for calculating the rebate that a service provider must proactively award to a customer when the SLA is breached are not new. There is not, however, a tool or process available to service providers for minimizing the total rebate a service provider awards in the event of an SLA breach.
Rebates in the form of monetary compensation, free software, or other forms, are costly to service providers. Rebates affect a provider's overall profitability as well impact the provider's goodwill. After all, those customers who have paid a premium price for service are not receiving the level of service agreed upon. These customers may suffer financial losses and losses of goodwill, as well, if they, in turn, cannot meet their business demands. Therefore, one skilled in the art should appreciate the advantages of an invention that precisely addresses the problem of minimizing rebates the service providers disburse to customers as a result of an SLA breach. This and other objects of the invention will be apparent to those skilled in the art from the following detailed description of a preferred embodiment of the invention.